Design of Fully Digital Controlled Reconfigurable Dual-Beam Concentric Ring Array Antenna Using Gravitational Search Algorithm

In this paper, we propose an optimization method based on Gravitational Search Algorithm (GSA) for design of reconfigurable dual-beam concentric ring array of isotropic elements with phase only control of five-bit digital phase shifters. The problem is to find a common radial amplitude distribution using four-bit digital attenuator that will generate three different types of broadsided beam pair in vertical plane: a pencil/pencil beam pair, a pencil/flat-top beam pair and a flat-top/flat-top beam pair sector pattern) with desired value of side lobe level, first null beam width and ripple. The two patterns differ only in radial discrete phase distribution while sharing a common discrete radial amplitude distribution. The optimum sets of four-bit discrete radial amplitude distribution generated by four-bit digital attenuators and five-bit discrete radial phase distribution generated by five-bit digital phase shifters for obtaining dual radiation patterns are computed by Gravitational Search Algorithm.